“Denny’s put out a grilled cheese sandwich that inside was not just grilled cheese but also mozzarella sticks. [And] Hardee’s put out a burger that had slices of steak and cheese and onions on the burger as the topping.”

In a 2006 press release, Hardee’s said: Condiments have always played an important role when it comes to creating a mouthwatering, palate-pleasing burger. So, the marriage of one of America’s favorite sandwiches to a Thickburger was no exception.

In fact, Hardee’s sister chain, Carl’s Jr, proved this with the successful launch of its Pastrami Burger [in 2005].” Glass continues: “Anyway, so these Frankenfoods have been around for a little while but there was a turning point when they kind of came into their own, and it was a sandwich called the Double Down – KFC put it out.

“This is the one where fried chicken is the bread of the sandwich with bacon and cheese in between. And with the Double Down, one of the things that created this turning point was, first of all, how extreme it was but also it became clear that the food industry was in on the joke, like the Double Down, it was self-aware of its own ridiculousness.

“Whenever I see an ad for one of these things I wondered, okay, if these things exist then somewhere there is a room where people debate which one they are going to do. What happens in that room? What is that discussion?”

The next part of the podcast sees producer Zoe Chace go to St Louis, to the headquarters of Hardee’s. where they had come up with a list of 200 concept burgers. She says: “The next thing is this team of executives votes up or down, based on the name of the burger, and they whittle this list down to about 30.

“The next step is the taste test. And in the taste test they make the burgers that they imagined up in that room. They eat the sandwiches, they discuss intensely and they decide which ones will be real, which ones are going to move forward, actually marketed, released into a few restaurants, tested on actual consumers and maybe go national.

“The room is a kitchen, a fast-food kitchen, an exact replica of what you would find at a Hardee’s. In the room are the men. Picture a group of slightly nerdy science teachers, but these guys are a big deal in their industry – they are trendsetters. For instance, meat as a condiment – these guys made that a thing.

“We each have a place setting and a printed menu. We will start with the Cinnamon Twirl French Toast breakfast sandwich – kind of a sweet and savoury combination. A Steak and Egg Biscuit after that, a Mac n Cheese Thickburger, a Steakhouse Thickburger, the Big Chicken Masher, Pepperoni Pizza Fries and a Ding Dong ice cream sandwich for dessert.”

Key to the process is “they have to maintain an appetite through the whole thing,” Zoe says. To achieve this, they use spit cups, like in a wine tasting. “Except it’s big plastic to-go cups full of chewed up burger. Bite, chew, spit,” explains Zoe.

“These guys aren’t chefs – they’re marketers. They [need to ask] will ‘America actually buy this thing?’ Which is answered in the look as much as the taste.” After trying the Bacon Mac n Cheese burger Zoe suggests that what is missing is hot sauce. The guys mull it over and agree to try it with a Buffalo Wing sauce.

Glass says: “There are a few reasons why guys like these are churning through these food mash-ups right now and one big one is fast-food is losing market share to places like Chipotle, more upscale, healthier. So a way for fast-food to compete is to go in the other direction.

“Downscale, greasier, sell to their core customers – 18 to 34-year-old guys, although industry analysts told me it is nearly as many women as men. And, of course, there is money to be made in selling a sandwich that people want to take a picture of themselves with while they eat it.

“But only to a point – the question is, will they eat it twice? The Double Down? As ground-breaking as it was, it didn’t sell that well after people tried it once. What they want is something that food industry people say Taco Bell did better than anyone in 2012 when they released that taco whose shell was a Dorito.

The Doritos Locos Tacos sold, and sold, and sold, and sold. US$375 million in its first year.”

Back in the room, one of the marketeers says: “This is the Big Chicken Masher – it’s got mashed potato and brown gravy on it some garlic pepper, onion straws, American cheese and our big chicken filet.”

Another guy says: “If we can’t come up with a name then it’s probably not going to sell. We run into that a lot, where we have a great product but what do you do with it?”

A third man says: “I’m not sure there is a market out there for people to eat mashed potatoes on a sandwich. But if they tasted it, I think they’d really like it. But it is not enough for a product to taste good – it has to sound good.”

For example, they highlight the “Pulled Pork burger”, which did not work well as a brand, and yet the “Memphis Barbecue” did. The Chicken Masher needs that story.

“Even the Mac n Cheese is an easier sell,” says the first guy. “Cheese is something people are already looking for on a burger, they expect on a burger, we have only thrown in one extra thing. Throwing in mashed potatoes and gravy is really not something anyone has seen on a chicken sandwich.”

Chace says: “The leap is greater. Mashed potatoes goes too far.”

All this said, just days ago Canadian chain The Works came up with this abomination – a beef patty stuffed with a Reese’s Peanut Butter Cup, topped crispy onions and bacon. Frankenfood, my friends, just got a whole lot weirder.